1. Field of the Invention
This invention relates to apparatus for making envelopes of the open end type and more particularly to an attachment to a closure flap folding apparatus that includes provision for gumming and folding an envelope blank to make open end envelopes.
2. Description of the Prior Art
Envelope making machines are known for folding the closure flap after the side and bottom flaps of the envelope blank have been folded and adhesively secured to the body portion as illustrated in U.S. Pat. No. 3,641,883. With other known conventional envelope making machines closure flap folding devices include belts, pressure rollers and the like, which apply forces upon the envelope while the envelope is conveyed through the closure flap folding cylinder. U.S. Pat. No. 1,943,985 illustrates a machine for making open end envelopes and includes a plurality of pressure rollers, belts, and extended conveying paths. Devices such as illustrated in U.S. Pat. No. 1,961,162 are also known for applying adhesive to envelope blanks for securing together the various folded flaps of the envelope blanks.
While it is known to make open end envelopes and apply adhesives to various flaps of the envelope, such devices are complex, expensive to manufacture and difficult to maintain in the manufacture of open end envelopes. There is need for apparatus that may be easily converted from closure flap folding operations to open end envelope making operations.